A Novel Warped-Beam Design that Enhances RF Performance of Capacitive MEMS Switches

This paper presents the design, fabrication and testing of a novel electrostatically actuated capacitive shunt switch for X-band applications. By introducing warped bimetallic beams within the switch´s geometry, the effective capacitive area is optimized to fine-tune the switch´s RF performance in the ´off´ state without influencing the switch´s ´on´ state performance. As a result, measurements show a drastic improvement where the down-state capacitance is doubled and the up-state capacitance is halved. Using this technique, a dual-warped switch with an off-to-on capacitive ratio of almost 170 is achieved without the need for thin dielectrics or high dielectric constant materials, exhibiting excellent RF performance and mechanical reliability.